<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>


<style>
   .neirong {
       width: 500px;
       height: 500px;
      background-color: yellowgreen;
      text-align: center;
       
    
       
   }
</style>
<body>

<h1>留言板</h1>


<div class="neirong">
    <button ></button>
    <h1>留言内容</h1>
    
   <div>

    </div>


</div>
<button>提交</button>








    
</body>

</html>